Conventionally, there exists a contactless power receiving apparatus including: a resonance element adapted to receive supply of alternating-current power in a contactless fashion by resonance from a resonance element of a power supplying source; an excitation element adapted to receive supply of the alternating-current power by electromagnetic induction from the resonance element; a rectification circuit adapted to generate direct-current power from the alternating-current power from the excitation element and output the direct-current power; and a changeover circuit adapted to change over the alternating-current power to the rectification circuit between a supply state and a non-supply state (see Patent Document 1, for example).
However, for the conventional contactless power receiving apparatus (power receiver), an efficiency of electric power reception when the resonance element receives electric power transmitted to the power receiver is not considered. Because the efficiency of electric power reception is changed depending on a position, orientation, or the like of the power receiver with respect to a power transmitter, when electric power is transmitted without considering the efficiency of electric power reception especially in a case where a plurality of power receivers are present, it may become impossible to supply the electric power to the plurality of power receivers in a balanced manner.